Medical devices that include a medicament have been known. Examples include contact lenses and stents for the treatment or prevention of a variety of diseases, disorders or conditions, such as contact lenses for the treatment of glaucoma and stents for the treatment or prevention of restinosis. Existing medical devices that include medicaments are traditionally made using relatively simple drug coating or drug impregnation technologies that do not allow the modulated release of the medicament from the coating. The present invention addresses these limitations and provides additional benefits as well.
A variety of medical devices, particularly contact lenses, that include a medicament have been described. For example, U.S. Pat. No. 7,638,137B2 to Chuahan et al. describes drug delivery systems through dispersion of transparently encapsulated drugs within the lens. However, such dispersion inside the lens could alter the physical properties of the polymeric lens materials. Also, while encapsulated drugs may be visually transparent in certain instances, the may interfere with the optical properties of the lens. Also, drugs inside the lens may be released from either or both the anterior and posterior surfaces of the lens and thus not providing the desired dosage of a drug to the cornea or other areas of an eye structure and surrounding tissues. This document also provides a survey of the literature relating to issues relating to drug release.
U.S. published Patent Application No. 2009/07504245A1 to Orilla et al. describe the masking of a color of a drug by applying a color layer on top of the drug. This document does not relate to the controlling the drug release rate from the lens.
Also, U.S. published Patent Application No. 2009/0004244 to Burke et al. describes deposing a drug in an iris simulated pattern to provide a cosmetic appearance of a lens for drug delivery. This document does not relate to how drug release rate can be controlled.
In addition, U.S. Pat. No. 6,887,858 to Yerxa describes formulations for the treatment of dry eye diseases. The document is not related to drug release from a medical device such as a contact lens.
Furthermore, U.S. Pat. No. 6,294,553 to Gil et al. describes a drug for ocular surface pain. Gil et al. does not, however relate to controlled drug delivery rate.
U.S. Pat. No. 3,786,812 to Neefe describes the use of contact lenses for drug delivery. This document, however, does not relate to achieving desired release rate of a drug from a lens.
Also, U.S. Pat. No. 3,618,604 and U.S. Pat. No. 3,828,777 describe polymeric plastics in which a drug is held to provide controlled drug release rate. The documents, however, do not relate to the ability to adjust drug release rate.